Following miniaturization of semiconductor devices, an interconnect pattern smaller than a limit dimension of the resolution of lithography is demanded to be formed. A sidewall transfer technique is known as one of techniques of forming a fine interconnect pattern.
The sidewall transfer technique can form a pattern having a dimension smaller than the limit dimension (line width or pitch) of the resolution of lithography.
A method is also proposed which forms a pattern having a dimension which is the one fourth of the resolution limit of lithography or less by repeating the sidewall transfer process a plurality of times.
For example, a line-and-space pattern such as a pattern of a memory cell array of a flash memory is formed by the sidewall transfer technique. In an area for connecting peripheral circuits and the memory cell array, a contact pattern is formed to be connected with an interconnect pattern (line pattern) drawn from the memory cell array. The dimension of the contact pattern is preferably greater than the dimension of the interconnect, pattern.
Meanwhile, in a process which is common to a manufacturing process to which the sidewall transfer technique for forming the line-and-space pattern is applied, it is difficult to form a contact pattern having a different dimension from the line pattern.